Multicomponent Synergistic Antibacterial Hydrogel Based on Gelatin-Oxidized Carboxymethyl Cellulose for Wound Healing of Drug-Resistant Chronic Infection.

Bacterial invasion hinders the healing process of wound, leading to the formation of chronic infected wound; meanwhile, the misuse of antibiotics has resulted in the emergence of numerous drug-resistant bacteria. The application of conventional antimicrobial methods and wound treatment techniques is not appropriate for wound dressings. In this paper, quaternized poly(vinyl alcohol) (QPVA) and pomegranate-like copper uniformly doped polydopamine nanoparticles (PDA@Cu) were introduced into a gelatin-oxidized carboxymethyl cellulose system to form a multicomponent synergistic antibacterial hydrogel (GOQ3P3). Polydopamine improves the biocompatibility and prevents the detachment of Cu nanoparticles. It can achieve synergistic antibacterial effects through quaternary ammonium salt-inorganic nanoparticle photothermal treatment under 808 nm near-infrared (NIR) irradiation. It exhibits highly efficient and rapid bactericidal properties against Escherichia coli, Staphylococcus aureus, and MRSA (methicillin-resistant Staphylococcus aureus) with an antibacterial rate close to 100%. The gel scaffold composed of macromolecules gives the hydrogel excellent mechanical properties, adhesive capabilities, self-healing characteristics, biocompatibility, and pH degradation and promotes cell adhesion and migration. In a full-thickness wound healing model infected with MRSA, GOQ3P3 controls inflammatory responses, accelerates collagen deposition, promotes angiogenesis, and enhances wound closure in the wound healing cascade reaction. This study provides a feasible strategy for constructing dressings targeting chronic infection wounds caused by drug-resistant bacteria.

A Light-Triggered J-Aggregation-Regulated Therapy Conversion: from Photodynamic/Photothermal Therapy to Long-Lasting Chemodynamic Therapy for Effective Tumor Ablation.

Reactive oxygen species (ROS) have become an effective tool for tumor treatment. The combination of photodynamic therapy (PDT) and chemodynamic therapy (CDT) takes advantage of various ROS and enhances therapeutic effects. However, the activation of CDT usually occurs before PDT, which hinders the sustained maintenance of hydroxyl radicals (⋅OH) and reduces the treatment efficiency. Herein, we present a light-triggered nano-system based on molecular aggregation regulation for converting cancer therapy from PDT/photothermal therapy (PTT) to a long-lasting CDT. The ordered J-aggregation enhances the photodynamic properties of the cyanine moiety while simultaneously suppressing the chemodynamic capabilities of the copper-porphyrin moiety. Upon light irradiation, Cu-PCy JNPs demonstrate strong photodynamic and photothermal effects. Meanwhile, light triggers a rapid degradation of the cyanine backbone, leading to the destruction of the J-aggregation. As a result, a long-lasting CDT is sequentially activated, and the sustained generation of ⋅OH is observed for up to 48 hours, causing potent cellular oxidative stress and apoptosis. Due to their excellent tumor accumulation, Cu-PCy JNPs exhibit effective in vivo tumor ablation through the converting therapy. This work provides a new approach for effectively prolonging the chemodynamic activity in ROS-based cancer therapy.

The synergetic effect of alginate-derived hydrogels and metal-phenolic nanospheres for chronic wound therapy.

Management of diabetic wounds presents a global health challenge due to elevated levels of ROS in the wound microenvironment, persistent dysregulation of inflammation modulation, and limitations in commercially available dressings. Addressing this issue, we have developed a pH-responsive and glucose-sensitive multifunctional hydrogel dressing that dynamically responds to the wound microenvironment and enables on-demand drug release. The dressing incorporates a matrix material based on aminophenylboronic acid-functionalized alginate and a polyhydroxy polymer, alongside an enhancer phase consisting of self-assembled metal-phenol coordination nanospheres formed by tannic acid and iron ions. Using the dynamic borate ester bonds and catechol-metal ion coordination bonds, the dressing exhibits remarkable shape adaptability, self-healing capability, tissue adhesiveness, antioxidant activity, and photothermal responsiveness, without additional curatives or crosslinking agents. As a wound dressing, it elicits macrophage polarization towards an anti-inflammatory phenotype while maintaining long-lasting antimicrobial effects. In a diabetic mouse model of full-thickness wound infections, it effectively mitigated inflammation and vascular damage, significantly expediting the wound healing process with a commendable 97.7% wound closure rate. This work provides a new direction for developing multifunctional smart hydrogel dressings that can accelerate diabetic wound healing for human health.

Dehydration-Toughing Dual-Solvent Gels with Viscoelastic Transition for Infectious Wound Treatment.

The modulus of traditional biomedical hydrogels increases exponentially meditated by dehydration-stiffing mechanism, which leads to the failure of interface matching between hydrogels and soft tissue wounds. It is found in the study that the dual-solvent gels exhibit dehydration-toughening mechanism with the slowly increasing modulus that are always match the soft tissue wounds. Therefore, dual-solvent glycerol hydrogels (GCFen-gly DGHs) are prepared with hydrophobically modified catechol chitosan (hmCSC) and gelatin based on the supramolecular interactions. GCFen-gly DGHs exhibit excellent water retention capacity with a total solvent content exceeding 80%, permanent skin-like modulus within a range of 0.45 to 4.13 kPa, and stable photothermal antibacterial abilities against S, aureus, E. coli, as well as MRSA. Infectious full-thickness rat skin defect model and tissue section analysis indicate that GCFen-gly DGHs are able to accelerate infectious wound healing by alleviating the inflammatory response, promoting granulation tissue growth, re-epithelialization, collagen deposition, and vascular regeneration. As a result, GCFen-gly DGHs is expected to become the next-generation biological gel materials for infectious wound treatment.

Dual-Drug-Loaded Core-Shell Electrospun Nanofiber Dressing for Deep Burns.

The epidermis of a deep burn wound is entirely absent and the dermal tissue sustains significant damage, accompanied by a substantial amount of tissue exudate. Due to the excessively humid environment, the formation of a scab on the wound becomes challenging, leaving it highly vulnerable to external bacterial invasion. In this work, a core-shell dual-drug-loaded nanofiber dressing was prepared by electrospinning technology for the synergistic treatment of a deep burn. The shell layer consists of polycaprolactone and chitosan encapsulating asiaticoside, with the core layer comprising the clathrate of 2-hydroxypropyl-ß-cyclodextrin and curcumin. Upon application to the wound, the dual-drug-loaded nanofiber dressing exhibited rapid release of asiaticoside, stimulating collagen deposition and promoting tissue repair. The core-shell structure and clathrate configuration ensured sustained release of curcumin, providing antibacterial and anti-inflammatory functions for the wound. The mechanical strength, broad-spectrum antibacterial ability, cell proliferation, and adhesion ability of the nanofiber dressing showed its potential as a medical dressing. This dressing also exhibited excellent wound healing promoting effects in the SD rat burn model. This paper provides a strategy for burn wound healing.

Network pharmacology and in vivo evidence of the pharmacological mechanism of geniposide in the treatment of atherosclerosis.

BACKGROUND: Atherosclerosis (AS) is a fundamental pathological state in various cardiovascular diseases. Geniposide, which is the main active component of Gardenia jasminides, is effective against AS. However, the underlying molecular mechanisms remain unclear. Here, we sought to elucidate them. METHODS: The targets of AS and geniposide were collected from online public databases. The potential mechanism of Geniposide in treating AS was predicted by constructing a protein-protein interaction (PPI) network and conducting Gene Ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway enrichment analyses. Hub proteins and core pathways were verified by molecular docking and in vivo experiments. Moreover, the effect of geniposide on AS was assessed by measuring the atherosclerotic plaque area in the thoracic aorta of mice. ApoE-/- mice were used to establish AS models and randomly divided into different groups. Two different doses of geniposide were administered to the mice. Hematoxylin and eosin (HE) staining was performed to evaluate the effects of geniposide on AS. Oil Red O and Sirius Red staining were used to evaluate plaque stability. The protein expression of key markers involved in the signalling pathways was examined using western blotting and immunofluorescence. RESULTS: A total of 239 active targets, 3418 AS-related disease targets, and 129 overlapping targets were identified. Hub genes were detected, and molecular docking revealed that geniposide strongly interacted with hub proteins (AKT1, VEGFA, CTNNB1, MMP9, and EGFR). Moreover, 109 signalling pathways, including the Rap1 signalling pathway, were identified using enrichment analysis. The results of in vivo experiments demonstrated that geniposide reduced body weight and blood lipid levels, alleviated the formation of atherosclerotic plaques, enhanced plaque stability, and inhibited inflammation, at least partially, by activating the Rap1/PI3K/Akt signalling pathway in ApoE-/- mice. CONCLUSION: Geniposide can alleviate AS and enhance the stability of atherosclerotic plaques by regulating the Rap1/PI3K/Akt signalling pathway.

Multifunctional Bacterial Cellulose/Covalent Organic Framework Composite Membranes with Antifouling and Antibacterial Properties for Dye Separation.

Covalent organic frameworks (COFs) have a wide application prospect in wastewater treatment because of their unique structure and properties; however, the preparation of pure COF membranes remains a great challenge by reason of the insolubility and unprocessability of COF powders formed at high temperature and high pressure. In this study, a continuous and defect-free bacterial cellulose/covalent organic framework composite membrane was prepared by using bacterial cellulose (BC) and a porphyrin-based COF with their unique structures and hydrogen bonding forces. The dye rejection rate of this composite membrane toward methyl green and congo red was up to 99%, and the permeance was about 195 L m-2 h-1 bar-1. It showed excellent stability under different pH conditions, long-time filtration, and cyclic experimental conditions. In addition, the hydrophilicity and surface negativity of the BC/COF composite membrane made it have certain antifouling performance, and the flux recovery rate can reach 93.72%. More importantly, the composite membrane exhibited excellent antibacterial properties due to the doping of the porphyrin-based COF, and the survival rates of both Escherichia coli and Staphylococcus aureus were less than 1% after exposure to visible light. The self-supporting BC/COF composite membrane synthesized by this strategy also has outstanding antifouling and antibacterial properties, in addition to excellent dye separation effects, which greatly broaden the application of COF materials in water treatment.

Injectable In Situ Photocrosslinked Hydrogel Dressing for Infected Wound Healing.

A traditional injectable photocrosslinked hydrogel had disadvantages of the residual photoinitiator and toxic crosslinker, slow in situ curing, and a complex preparation process. At the same time, hydrogels cannot act as artificial skin to restore skin sensory function during the wound healing cycle. In this work, an injectable photocrosslinked hydrogel was prepared which can be quickly in situ cured without photoinitiator. Oxidized sodium alginate was used as a natural macromolecular crosslinking agent to form an injectable hydrogel framework with the photosensitive polymer polyvinyl alcohol bearing styrylpyridinium group (PVA-SBQ). In addition, the hydrogel was endowed with photothermal therapy property after the introduction of biomass-like polydopamine particles. When used as a wound dressing, the hydrogel exhibited an excellent antibacterial property, with an antibacterial rate of 99.56% Escherichia coli and 97.96% Staphylococcus aureus. As a result, the hydrogel could significantly accelerate the repair of infected wounds, with a wound healing rate of 96.45% after 14 days. Moreover, the hydrogel exhibited a sensitive and stable sensing property, making it promising to reconstitute the sensory function of damaged skin during treatment. This work provides an idea for the development of injectable photocrosslinked hydrogel dressing.

3D Interconnected Honeycomb-Like Multifunctional Catalyst for Zn-Air Batteries.

Developing high-performance and low-cost electrocatalysts is key to achieve the clean-energy target. Herein, a dual regulation method is proposed to prepare a 3D honeycomb-like carbon-based catalyst with stable Fe/Co co-dopants. Fe atoms are highly dispersed and fixed to the polymer microsphere, followed by a high-temperature decomposition, for the generation of carbon-based catalyst with a honeycomb-like structure. The as-prepared catalyst contains a large number of Fe/Co nanoparticles (Fe/Co NPs), providing the excellent catalytic activity and durability in oxygen reduction reaction, oxygen evolution reaction and hydrogen evolution reaction. The Zn-air battery assembled by the as-prepared catalyst as air cathode shows a good charge and discharge capacity, and it exhibits an ultra-long service life by maintaining a stable charge and discharge platform for a 311-h cycle. Further X-ray absorption fine structure characterization and density functional theory calculation confirms that the Fe doping optimizes the intermediate adsorption process and electron transfer of Co.

Red meat consumption and risk for dyslipidaemia and inflammation: A systematic review and meta-analysis.

Aim: The study (PROSPERO: CRD42021240905) aims to reveal the relationships among red meat, serum lipids and inflammatory biomarkers. Methods and results: PubMed, EMBASE and the Cochrane databases were explored through December 2021 to identify 574 studies about red meat and serum lipids markers including total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), C-reactive protein (CRP) or hypersensitive-CRP (hs-CRP). Finally, 20 randomized controlled trials (RCTs) involving 1001 people were included, red meat and serum lipid markers and their relevant information was extracted. The pooled standard mean difference (SMD) was obtained by applying a random-effects model, and subgroup analyses and meta-regression were employed to explain the heterogeneity. Compared with white meat or grain diets, the gross results showed that the consumption of red meat increased serum lipid concentrations like TG (0.29 mmol/L, 95% CI 0.14, 0.44,P<0.001), but did not significantly influence the TC (0.13 mmol/L, 95% CI -0.07, 0.33, P = 0.21), LDL-C (0.11 mmol/L, 95% CI -0.23, 0.45, P = 0.53), HDL-C (-0.07 mmol/L, 95% CI -0.31, 0.17, P = 0.57),CRP or hs-CRP (0.13 mmol/L, 95% CI -0.10, 0.37,P = 0.273). Conclusion: Our study provided evidence to the fact that red meat consumption affected serum lipids levels like TG, but almost had no effect on TC, LDL-C, HDL-C and CRP or hs-CRP. Such diets with red meat should be taken seriously to avoid the problem of high lipid profiles. Systematic review registration: [https://www.crd.york.ac.uk/PROSPERO], identifier [CRD42021240905].

Glycosaminoglycan-Based Hydrogel Delivery System Regulates the Wound Microenvironment to Rescue Chronic Wound Healing.

Chronic wounds cannot proceed through the normal, orderly, and timely sequence of repair. The adverse cycle between excess reactive oxide species (ROS) and a persistent inflammatory response is an important mechanism of impaired wound healing. Herein, by combining the intrinsic bioactivities of natural polysaccharides and natural drugs, a glycosaminoglycan-based hydrogel delivery system is proposed to regulate the wound microenvironment. Dynamic supramolecular cross-linking enables the hydrogel to easily encapsulate the drug and fully fill the wound area. As the backbone of the hydrogel, heparin captures inflammatory chemokines at the wound site, while hyaluronic acid mimics the function of ECM. The hydrophobic drug curcumin has been ingeniously encapsulated in the hydrogel through micellization, thereby exerting good ROS scavenging ability and anti-inflammatory activity. Evaluations in diabetic mice showed that this antioxidant and anti-inflammatory hydrogel was effective in reducing the influx of immune cells at the wound site and in down-regulating the inflammatory response. Accelerated wound healing was also observed, as evidenced by faster re-epithelialization and better ECM remodeling. The proposed hydrogel can regulate the microenvironment of wounds from multiple aspects and thereby achieve regression of wound repair, which may provide a new therapeutic strategy for chronic wounds.

A Review: Current Status and Emerging Developments on Natural Polymer-Based Electrospun Fibers.

In recent years, natural polymer-based electrospun fibers (EFs) with huge specific surface area, good biocompatibility, and biological activity obtained from electrospinning process exhibit tremendous vitality in the field of biomedical areas. Herein, the parameters of electrospinning from two perspectives, polymer solution such as solvent, polymeric relative molecular mass, concentration, viscosity, and conductivity of the solution, and electrospinning process such as spinning voltage, spinning flow rate, needle tip to collector distance, temperature, and humidity are first detailed. Next, the raw materials consisting of polysaccharides such as cellulose, hyaluronic acid, alginate, and chitosan as well as proteins such as collagen, gelatin, silk fibroin, and keratin are summarized. The preparation method and related characteristics of EFs with multistage structures such as porous, core-shell, Janus, bamboo-like and other structures are introduced. The biomedical applications of these natural polymer-based EFs mainly including tissue engineering, drug sustained release, wound dressings, and biomedical sensors are systematically recapitulated. Finally, the outlook on natural EFs is further proposed.

Targeting polysaccharides such as chitosan, cellulose, alginate and starch for designing hemostatic dressings.

Unfortunately hemorrhage and its complications (e.g. anemia, organ failure, and hypothermia) induced by traumatic injury, surgery, and disorders of bleeding play an all too familiar role in human morbidity and mortality. Therefore, it is difficult to overstate the importance of better understanding the role of polysaccharides in advanced hemostatic dressings (HDs). This review includes consideration of polysaccharide hemostatic dressing mechanism of action, relative efficacy, cost and safety. Polysaccharide-based HDs are widely used in management not only of external and internal bleeding but also of massive hemorrhage. These polysaccharide-based HDs have been shown to be effective in both compressible and non-compressible hemorrhage. Hemostatic dressings are designed with different principles depending on location and extent of injury. This review focuses on polysaccharide HD design and associated hemostatic mechanisms. It addresses current issues, challenges, and future perspectives.

A heptamethine cyanine with meso-N-induced rearrangement for acid-activated tumour imaging and photothermal therapy.

Photothermal therapy has been developed as one of the most attractive strategies for tumour therapy. However, most of the reported photothermal probes still suffer from poor selectivity or specificity for the tumour region during treatment. Herein, a tumour acidic microenvironment activated heptamethine cyanine-based nanoprobe (Cy-TPA NPs) is constructed for fluorescence imaging-guided photothermal therapy with enhanced tumour specificity. Taking advantage of the pH-dependent molecular rearrangement, Cy-TPA NPs under weak acidic conditions exhibit enhanced near-infrared absorption and "turn on" fluorescence and photothermal performance. The "turn on" fluorescence signal in tumour tissues can improve the signal-to-background ratio, providing precise in vivo fluorescence imaging. Moreover, tumour-specific PTT can effectively ablate tumours with reduced damage to the surrounding tissue. Thus, our work presents a promising strategy for significantly improving the precision and specificity of tumour imaging and therapy.

Smart Polycationic Hydrogel Dressing for Dynamic Wound Healing.

It is challenging for traditional wound dressings to adapt to the complex and changeable environment, due to the lack of stable, efficient, and continuous bactericidal activity. They also cannot be satisfied in a multifunctional sensing platform to reconstruct skin sensory functions for human health monitoring. A multifunctional hydrogel dressing is developed here for the treatment of infected wounds and human health monitoring, which is based on alginate and polycation. The in situ polymerization and solvent displacement method are used to functionalize the hydrogel for the improvement of antifreezing, water retention, and environmental adaptability, as well as the adhesion and photothermal property. As a wound dressing, the as-prepared hydrogel exhibits an excellent antibacterial property against both Escherichia coli and Staphylococcus aureus. In a rat model of full-thickness wound infection, it significantly accelerates the healing of infected wounds with a high healing rate of 96.49%. In the further multifunctional sensory tests, the hydrogel shows multiple response modes of strain, pressure and temperature, and sensing stability. An idea is provided here to develop a smart hydrogel dressing that can accelerate wound healing and achieve human health monitoring.

Smart Hydrogel Sensors with Antifreezing, Antifouling Properties for Wound Healing.

Flexible electronic devices with biological therapeutic and sensing properties are one of the current research directions. Here, a multifunctional hydrogel for stress sensing and wound healing was prepared by a simple one-pot method and a solution replacement method. Among them, zwitterionic polymers promote wound healing by promoting the polarization of M2 macrophages, collagen deposition, and blood vessel formation. Glycerin can significantly improve the resilience and frost resistance of the hydrogel, ensuring that a sensor made using the hydrogel can work normally in a cold environment. In addition, zwitterionic polymers are highly biocompatible, providing excellent antibacterial adhesion to aid the wound healing process, and good electrical conductivity enhances sensing sensitivity and stability. Based on these properties, multifunctional hydrogels could detect human vital activities while promoting wound healing, providing new ideas for the fields of diagnosis and wound dressing.

Chitosan for constructing stable polymer-inorganic suspensions and multifunctional membranes for wound healing.

Restricted by the rigid chain structure, chitosan-based materials are very fragile and easy to break up. Herein, a stable and positively charged chitosan/Ti3C2Tx suspension was successfully constructed by adjusting mixing sequence, pH and ratio of chitosan to Ti3C2Tx to prepare a multifunctional membrane (P-CM) with self-standing ability, good flexibility, biocompatibility, excellent photothermal antibacterial properties, and sensitive humidity sensing properties. In the first stage, protonated chitosan acted as sugar coatings was able to be encapsulated on the surface of Ti3C2Tx nanosheets by electrostatic self-assembly, in turn achieving charge reversal of the nanoparticles. In the second stage, chitosan acted as molecular needles to suture the membrane formed by chitosan/Ti3C2Tx particles via vacuum filtration (VAF) with the commercial flexible poly(vinylidene fluoride) (PVDF) membrane. The as-prepared P-CM membrane simultaneously solves the problem of insufficient flexibility of a single component chitosan membrane and the poor bonding between pure Ti3C2Tx membranes and substrate membrane.

Bifunctional Smart Hydrogel Dressing with Strain Sensitivity and NIR-Responsive Performance.

Smart response hydrogel has a broad application prospect in human health real-time monitoring due to its responses to a variety of stimuli. In this study, we developed a novel smart hydrogel dressing based on conductive MXene nanosheets and a temperature-sensitive PNIPAm polymer. γ-Methacryloxypropyltrimethoxysilane (KH570) was selected to functionalize the surface of MXene further to improve the interface compatibility between MXene and PNIPAm. Our prepared K-M/PNIPAm hydrogel was found to have a strain-sensitive property, as well as a respond to NIR phase change and volume change. When applied as a strain flexible sensor, this K-M/PNIPAm hydrogel exhibited a high strain sensitivity with a gauge factor (GF) of 4.491, a broad working strain range of ≈250%, a fast response of ∼160 ms, and good cycle stability (i.e., 3000 s at 20% strain). Besides, this K-M/PNIPAm hydrogel can be used as an efficient NIR light-controlled drug release carrier to achieve on-demand drug release. This work paved the way for the application of smart response hydrogel in human health real-time monitoring and NIR-controlled drug release functions.

A natural polymer-based porous sponge with capillary-mimicking microchannels for rapid hemostasis.

Natural polymer materials have attracted great attention in the field of hemostasis because of their wide range of source, nontoxicity, hydrophilicity, and air permeability. In the present study, two natural polymers composed of carboxymethyl chitosan (CMCS) and sodium carboxymethylcellulose (CMCNa) plus γ-(2,3-epoxypropoxy) propytrimethoxysilane (KH560) that serves as a crosslinking agent were selected to synthesize a capillary-mimicking composite hemostatic (CCK) sponge with a low density, interconnected microchannel architecture, suitable mechanical strength, high resilience, and ultrastrong liquid absorption capacity. The introduction of a large number of hydrophilic carboxymethyl functional groups and the design of capillary-mimicking structures formed by the ice segregation-induced self-assembly (ISISA) process endowed the CCK sponges with an ultrastrong liquid absorption capacity, which significantly enhanced the hemostatic ability of the materials. Both in vivo and in vitro hemostatic experiments confirmed the potential of the CCK sponges to achieve rapid hemostasis. Additionally, cytotoxicity and hemolysis assays showed that the CCK sponges exhibited good biocompatibility and hemocompatibility. The possible hemostatic mechanism was also discussed in this study. In conclusion, the capillary-mimicking hemostatic sponge exhibits a high potential to induce rapid hemostasis in prehospital emergency and clinical settings. STATEMENT OF SIGNIFICANCE: In the present study, an oriented composite hemostatic (CCK) sponge with a capillary-mimicking structure formed by the ice segregation-induced self-assembly (ISISA) process was designed and used to achieve rapid hemostasis. The unique aligned microchannel structure of the sponge exhibited an ultrastrong capillary-mimicking action and endowed the prepared CCK hemostatic sponge with a strong liquid absorption capacity. By changing the proportion of raw materials, we could modify the unique capillary-mimicking structure with aligned microchannels. Two natural polymer-based materials with abundant hydrophilic groups were chosen to prepare the CCK sponge to fully utilize the characteristics of this structure. The oriented natural polymer-based porous sponge with capillary-mimicking microchannels exhibited a strong hemostatic ability in both in vivo and in vitro tests. The results showed that the CCK sponge with the capillary-mimicking structure has a high potential to achieve rapid hemostasis.

Hemp derived N-doped highly porous carbon containing Co nanoparticles as electrocatalyst for oxygen reduction reaction.

Biomass derived porous carbon was wildly used in non-precious metal carbon based electrocatalysts for ORR due to its low cost and sustainability. Here, we develop a facile route to prepare Co/N doped hemp derived highly porous carbon (Co/NHPC) as ORR electrocatalyst. The prepared Co/NHPC-90 possess 3D hierarchically porous nanostructure with high specific surface areas (1251 m2 g-1) and large pore volumes (0.99 cm3 g-1) due to the chemical activation of NaHCO3, which is benefit for the mass/electron transfer and exposure of active sites. In addition, melamine and cobalt nitrate were selected as nitrogen and metal source respectively to enrich the density of active sites. Thus, Co/NHPC-90 exhibits excellent ORR electrocatalytic performance with high half-wave potential (0.826 V), superior catalytic stability and tolerance to methanol.